Moderna has requested the US Food and Drug Administration (FDA) for emergency use authorisation (EUA) on the fourth dose of its Covid-19 vaccine for adults up to 18 years of age and older who already got a booster dose of any authorised dose.

The request was made to give flexibility for the US Centers for Disease Control and Prevention (CDC) and healthcare providers to pick the appropriate additional booster dose, including those at higher risk of Covid-19 due to age or comorbidities; the company said in a statement.

Currently, a booster dose of the Moderna vaccine is authorised by the FDA for emergency use in the United States for adults 1over eight years and older. The company said it continues to gather and monitor real-world data on its Covid-19 vaccine.